Implement SystemFunction006().
Add a test for SystemFunction006().

diff --git a/dlls/advapi32/crypt.h b/dlls/advapi32/crypt.h
index 74724ae..4a56363 100644
--- a/dlls/advapi32/crypt.h
+++ b/dlls/advapi32/crypt.h
@@ -79,4 +79,8 @@
 
 #define MAXPROVTYPES 999
 
+extern unsigned char *CRYPT_DESkey8to7( unsigned char *dst, const unsigned char *key );
+extern unsigned char *CRYPT_DEShash( unsigned char *dst, const unsigned char *key,
+                                     const unsigned char *src );
+
 #endif /* __WINE_CRYPT_H_ */